Ocular inserts (InEye®), were prepared based on two distinct formulations of PCL-PEG-PCL block copolymers - one with 33 % and the other with 24 % of PEG 600. Ring-open-polymerisation was used to link ε-caprolactone monomers to PEG hydroxyl end-groups. Molecular weight, PCL/PEG ratio, mass loss and swelling of different polymeric samples where determined. Based on the previously prepared block copolymers, ophthalmic inserts were assembled. These were prepared with an ellipsoidal shape by dripping melted polymer over a micro-tablet of moxifloxacin, used as drug model for this study, which therefore became entrapped in a central core coated with a polymer layer that functioned as a control-release barrier. The release kinetics of the model drug revealed a strong dependence on the PEG percentage on the polymer. Inserts' size and the amount of drug immobilized also had an important effect on the drug release profile. All release profiles followed a zero-order pattern, with 95 % of the drug being release at a constant rate. With drug releases varying from 20 to 200 days, and no initial burst, InEye® performance is unique among drug delivery systems and seems to be a very promising new formulation technology for preparing tailor-made ophthalmic inserts for prolonged and constant release of drug, which is needed for chronic diseases such as glaucoma, where compliance to treatment is essential for preventing optic-nerve lesions.

Polyurethanes (PUs) are extremely versatile materials used across different industries. Traditionally, they are synthesized by reacting polyols and isocyanates, both of which are petroleum-derived reagents. In response to the demand for more eco-friendly materials, research has increasingly focused on developing new routes for PU synthesis using renewable feedstocks. While substituting isocyanates remains a greater challenge, replacing fossil-based polyols with bio-based alternatives is now a promising strategy. This review explores the main natural sources and their transformations into bio-polyols, the incorporation of bio-fillers into PU formulations, and the production of non-isocyanate polyurethanes (NIPUs). Additionally, the study summarizes the growing body of research that has reported successful outcomes using bio-polyols in PU foams for distinct applications.

Currently, bone infections caused by diseases or injuries are a major health issue. In addition, the conventional therapeutic approaches used to treat bone diseases or injuries present several drawbacks. In the area of tissue engineering, researchers have been developing new alternative therapeutic approaches, such as scaffolds, to promote the regeneration of injured tissues. Despite the advantages of these materials, most of them require an invasive surgical procedure. To overcome these problems, the main focus of this work was to develop scaffolds for bone regeneration, which can be applied using injectable hydrogels that circumvent the use of invasive procedures, while allowing for bone regeneration. Throughout this work, injectable hydrogels were developed based on a natural polymer, dextran, along with the use of two inorganic compounds, calcium β-triphosphate and nanohydroxyapatite, that aimed to reinforce the mechanical properties of the 3D mesh. The materials were chemically characterized considering the requirements for the intended application: the swelling capacity was evaluated, the degradation rate in a simulated physiological environment was assessed, and compression tests were performed. Furthermore, vancomycin was incorporated into the polymeric matrices to obtain scaffolds with antibacterial performance, and their drug release profile was assessed. The cytotoxic profile of the hydrogels was assessed by an MTS assay, using osteoblasts as model cells. The data obtained demonstrated that dextran-based hydrogels were successfully synthesized, with a drug release profile with an initial burst between 50 and 80% of the drug. The hydrogels possess fair biocompatibility. The swelling capacity showed that the stability of the samples and their degradation profile is compatible with the average time period required for bone regeneration (usually about one month) and have a favorable Young’s modulus (200–300 kPa). The obtained hydrogels are well-suited for bone regeneration applications such as infections that occur during implantation or bone graft substitutes with antibiotics.

Sugar-based polyurethane (PU) foams represent an important advancement in structured materials offering a more sustainable alternative to traditional PU foams derived from petro-based polyols. These PU foams can hold particular importance in fields such as construction, packaging, biomedical materials, and medical devices. Hitherto, the development relies on a trial-and-error basis or, at most, by changing one-factor-at-a-time (OFAT). Unfortunately, these methods are inefficient and prone to miss the intended goals. In this study, we apply a Quality by Design (QbD) strategy, integrating systematic experimental design and data-driven approaches, to optimize sugar-based PU foam formulations for integration into a pathogen-monitoring device and identify key factors affecting their properties. The effects of surfactant, water, catalyst, chain extender, and isocyanate concentrations were evaluated using statistical design of experiments (DoE), and the amount of water was identified as the most influential factor. An optimized formulation was obtained with 0.58% (w/w) water, 5.69% (w/w) surfactant, and 34.26% (w/w) toluene diisocyanate (TDI), with butanediol excluded due to its minor impact on foam’s performance and the water being the most impactful factor. This optimized formulation was synthesized and validated with the final material being able to absorb liquids, support capillary flow, and maintain physical integrity and glucose content. This approach enabled the tailored development of sugar-based PU foams to meet the specific application requirements.